Use @Native annotation on dart2js DOM native classes

tools/dom/scripts/systemhtml.py

 #!/usr/bin/python
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 """This module provides shared functionality for the system to generate
 Dart:html APIs from the IDL database."""
 
 import emitter
 import logging
@@ skipping 661 matching lines @@
     pass
 
   def AdditionalImplementedInterfaces(self):
     implements = super(Dart2JSBackend, self).AdditionalImplementedInterfaces()
     if self._interface_type_info.list_item_type() and self.HasIndexedGetter():
       implements.append('JavaScriptIndexingBehavior')
     return implements
 
   def NativeSpec(self):
     native_spec = MakeNativeSpec(self._interface.javascript_binding_name)
-    return ' native "%s"' % native_spec
+    return '@Native("%s")\n' % native_spec
 
   def ImplementationTemplate(self):
     template_file = ('impl_%s.darttemplate' %
                      self._interface.doc_js_name)
     return (self._template_loader.TryLoad(template_file) or
             self._template_loader.Load('dart2js_impl.darttemplate'))
 
   def StartInterface(self, members_emitter):
     self._members_emitter = members_emitter
 
@@ skipping 573 matching lines @@
 
   def AddFile(self, basename, library_name, path):
     self._libraries[library_name].AddFile(path)
 
   def AddTypeEntry(self, library_name, idl_name, dart_name):
     self._libraries[library_name].AddTypeEntry(idl_name, dart_name)
 
   def Emit(self, emitter, auxiliary_dir):
     for lib in self._libraries.values():
       lib.Emit(emitter, auxiliary_dir)